Please help ID type of nudi

drewsreef · Dec 18, 2023

Hello i was looking at my tank with the ligjts off and noticed some white spots on my christmas tree worm rock that has what i believe is a porites coral. As i looked closer i noticed thry looked like nudibranchs with white sac looking things. Idk what kind they are so i pulled them out and put them in a container. Ive had the christmas tree worm coral for a month and never noticed these before.

IKD · Dec 18, 2023

Those are nudibranchs. The harmless ones are very difficult to keep and the non-reef safe ones should be removed to protect your coral. I don’t know the exact I.D., but I see they are wondering on coral in the last picture and would not take any chances.

Pest Nudibranchs in Reef Aquaria

There are many different types of pests that can infect a reef aquarium, but I wanted to put a focus on coral eating nudibranchs. I didn’t even know to look out for these little mollusks until some have been observed eating away at our montipora colonies at the aquaculture facility. It is...

absolutelyfishnaturals.com

IKD · Dec 18, 2023

They almost look like berghia (only eat aiptasia), but will defer to more experienced folks on here

kevgib67 · Dec 18, 2023

@WheatToast ?

EeyoreIsMySpiritAnimal · Dec 18, 2023

drewsreef said:
Hello i was looking at my tank with the ligjts off and noticed some white spots on my christmas tree worm rock that has what i believe is a porites coral. As i looked closer i noticed thry looked like nudibranchs with white sac looking things. Idk what kind they are so i pulled them out and put them in a container. Ive had the christmas tree worm coral for a month and never noticed these before.

Look up "Phestilla minor". Apparently they like to eat porites...

drewsreef · Dec 19, 2023

IKD said:
Those are nudibranchs. The harmless ones are very difficult to keep and the non-reef safe ones should be removed to protect your coral. I don’t know the exact I.D., but I see they are wondering on coral in the last picture and would not take any chances.

Pest Nudibranchs in Reef Aquaria

There are many different types of pests that can infect a reef aquarium, but I wanted to put a focus on coral eating nudibranchs. I didn’t even know to look out for these little mollusks until some have been observed eating away at our montipora colonies at the aquaculture facility. It is...

absolutelyfishnaturals.com

EeyoreIsMySpiritAnimal said:
Look up "Phestilla minor". Apparently they like to eat porites...

Thanks so much looks identical to it. Will have to keep a close eye on the porites. Good thing i removed them

DaJMasta · Dec 19, 2023

Just their presence on the porites means they are likely a predator of it. If you can see adults, you likely already have eggs.

What I would do: take the porites out of the tank and give them a dip that will kill the adults every 2-3 days for a few weeks. The idea is to kill them in the juvenile stage and not let them lay more eggs, then just trying to outlast the eggs that are already there. There are some better explanations about nudibranch treatment regimes out there for more specifics.

I don't know if dips, especially repeated dips, would harm the worms in the rock. There's certainly a chance of it, but unless you've got pretty active predators of the nudis, you will likely lose your porites to them (though, nothing else).

It's not going to be an overnight thing, and it's probably worth looking closely at the coral for tissue damage (and other porites if you've got it) as well as trying to get a more positive ID, but if it's a corallivore nudibranch, the known treatment regimes are usually pretty involved, and it's important to not just underestimate it since acting quickly will give you a substantial leg up. Just removing adults daily may afford you some time before you decide what to do, but I would expect to see more, and you will never remove all of them manually.

A writeup that illustrates this point: http://www.seaslugforum.net/find/phesmino

Studies I did in Tanzania showed that P. minor grows rapidly (2 to 9mm in ten days) and starts egg-laying at between 6-9mm. Animals tend to form pairs, (as in P. lugubris), and produce about 10 egg masses, each mass having about 120 eggs. Lecithotrophic (non-feeding) veligers hatch after about seven days and remain in the plankton for a very short time(3-4 days).

That they have a veliger stage means that maybe heavy, fine mechanical filtration could help, but it also means that hatching eggs will spread throughout the tank and will probably only live to adults if they land near a food source, so killing the adults before they reproduce should be a reliable strategy.

drewsreef · Dec 21, 2023

DaJMasta said:
Just their presence on the porites means they are likely a predator of it. If you can see adults, you likely already have eggs.

What I would do: take the porites out of the tank and give them a dip that will kill the adults every 2-3 days for a few weeks. The idea is to kill them in the juvenile stage and not let them lay more eggs, then just trying to outlast the eggs that are already there. There are some better explanations about nudibranch treatment regimes out there for more specifics.

I don't know if dips, especially repeated dips, would harm the worms in the rock. There's certainly a chance of it, but unless you've got pretty active predators of the nudis, you will likely lose your porites to them (though, nothing else).

It's not going to be an overnight thing, and it's probably worth looking closely at the coral for tissue damage (and other porites if you've got it) as well as trying to get a more positive ID, but if it's a corallivore nudibranch, the known treatment regimes are usually pretty involved, and it's important to not just underestimate it since acting quickly will give you a substantial leg up. Just removing adults daily may afford you some time before you decide what to do, but I would expect to see more, and you will never remove all of them manually.

A writeup that illustrates this point: http://www.seaslugforum.net/find/phesmino

That they have a veliger stage means that maybe heavy, fine mechanical filtration could help, but it also means that hatching eggs will spread throughout the tank and will probably only live to adults if they land near a food source, so killing the adults before they reproduce should be a reliable strategy.

Appreciate the info...I have been removing more since i found the first pair. And from what ive read im pretty sure they are porites eating nudis. Im still thinking of what to do since im worried of losing the christmas tree worms by dipping the coral which is the reason i got the coral.

vetteguy53081 · Dec 21, 2023

Looks like a dorid or dirona species and yes, should be eliminated

ReefingDreams · Dec 21, 2023

drewsreef said:
Appreciate the info...I have been removing more since i found the first pair. And from what ive read im pretty sure they are porites eating nudis. Im still thinking of what to do since im worried of losing the christmas tree worms by dipping the coral which is the reason i got the coral.

Just keep manually removing them. I don't recommend dipping the rock. Any dip that will kill/stun a nudi will likely be an issue for the worms. If you lose the porites, they'll die off and you can start a new/prettier encruster on it.

drewsreef · Dec 21, 2023

ReefingDreams said:
Just keep manually removing them. I don't recommend dipping the rock. Any dip that will kill/stun a nudi will likely be an issue for the worms. If you lose the porites, they'll die off and you can start a new/prettier encruster on it.

Probably what ill do hate to lose coral to nudis =/